Justin Timberlake ‘ninja’ tweet angers Madonna fans

Looks like another celebrity needs to stay off of social media. On Monday, Us Weekly reported that Justin Timberlake is feeling some Twitter heat after a weekend birthday greeting to Madonna. In honor of the Material Girl’s 56th birthday, Timberlake reportedly took to Twitter to post: “A happiest of Bdays to my mother chucking ninja, @Madonna!! Hope you have a great one, M!" But the post was promptly deleted after followers called the singer out for using a word that is sometime known as a substitute for the n-word.

While Timberlake hasn’t publicly apologized for the social media snafu, he is one star who has no problem admitting a faux pas. In 2012, the "Cry Me a River" singer posted an open letter on his website to apologize for an offensive video that was made in honor of his wedding to Jessica Biel. The video featured several vagrants, transsexuals and street musicians giving wedding greetings to the A-list Hollywood couple, and while Timberlake maintained he had no part in making the clip, he apologized for the offensive material.

According to the New York Daily News, Timberlake wrote, "I am deeply sorry to anyone who was offended by the video. Again, it was something that I was not made aware of. But, I do understand the reaction and, by association, I am holding myself accountable."

Timberlake’s Twitter troubles come a month after Travel Channel host Adam Richman found himself in hot water for tweeting a word that’s sometimes used to describe eating disorders. Richman then got into a Twitter war with haters who called him out for the controversial hashtag. The “Man v. Food” host later apologized for his “inexcusable” remarks, like telling one user to “grab a razor and draw a bath.” But the apology wasn’t accepted. The damage was done and Richman’s latest Travel Channel show was pulled.

Comedian Patton Oswalt went a step further when his social media remarks about the UC Santa Barbara shootings enraged some followers in May. Rolling Stone revealed that “The Goldbergs” star decided to take a much needed break from both Facebook and Twitter until after Labor Day following his controversial exchange with followers. He signed off with a final tweet that directed followers to a Facebook post for all of the details: “I’m going radio silent until Tuesday, September 2nd,” he wrote.

Of course, even the object of Timberlake’s birthday greeting has had her own share of social media snags. Earlier this year, Rolling Stone reported that Madonna posted an Instagram pic of her 13-year old son Rocco in a boxing ring, and she included a racial slur in the caption: "No one messes with Dirty Soap! Mama said knock you out! #disn----,” she wrote.

After receiving massive backlash, the singer reportedly changed the caption, but then went on to post a full-on apology that said: "I am sorry if I offended anyone with my use of the N word on Instagram. It was not meant as a racial slur. I am not a racist. There's no way to defend the use of the word ... It was all about intention. It was used as a term of endearment toward my son who is white. I appreciate that it's a provocative word and I apologize if it gave people the wrong impression. Forgive me."